Recently, usage of car navigation systems for vehicles has been widespread. In those recent developments, apparatuses, which offer assistance to occupants of vehicles through use of car navigation systems, have been provided. Not only can the monitors provide geographic information, but also a rear view of the vehicle, and a view of portions that are hidden in blind spots of the vehicle, when the vehicle is about to be parked or being parked. In such apparatuses, the occupant's attention can be captured in order to recognize a view of what is hidden in a blind spot, and an occupant can therefore be warned of a presence of an obstacle, thus enhancing a safe driving operation. Further, if the occupant can have a rear view of the vehicle from a monitor that is normally mounted in front of the occupant, for example attached to an instrument panel, the occupant does not have to twist his body when parking the vehicle backwardly, therefore less driving load is applied to the occupant who is allowed to drive in normal driving posture.
Moreover, various types of driving support apparatuses have been provided, which not only display and provide information, described above, to the occupant, but also attempt to improve a safety level through an active control of driving operations of vehicles, such as an acceleration operation, a steering operation, a brake operation and so on. A parking operation support apparatus disclosed in JP2000-136738A (paragraphs 1-10) is an example of such apparatuses. This apparatus mainly supports a driving operation of an occupant especially when a vehicle is parked or when a vehicle, which has been parked, is started. For example, concerning an acceleration operation, control characteristics of an acceleration control mechanism is modified in such a manner that an upper limit of an opening degree of a throttle valve, or a gain for a valve opening degree, is lowered. As a result, even when an occupant erroneously operates an accelerator pedal excessively at a time of parking or starting, the control mechanism is able to restrain a sudden acceleration or starting of a vehicle.
As described above, by altering control characteristics of an acceleration control mechanism, a sudden starting, which may occur due to an excessive acceleration operation by an occupant, can be restrained. However, if the occupant continues the acceleration operation, a vehicle speed may be raised gradually. Especially when the occupant intends to park the vehicle very close to a wall or gutter, it is preferable to avoid that the vehicle passes by a target stop position. Therefore, in such circumstances, a slow speed driving of a vehicle is required. Meanwhile, a certain level of skills or experiences is required in order to implement a vehicle driving operation while maintaining a slow-speed driving and controlling a distance of the vehicle against the wall or gutter. In the light of the foregoing, it is preferable that driving support apparatuses support a vehicle driving operation of an occupant, especially when such skills or experiences are required. So far, the parking operation support apparatus disclosed in JP2000-136738A can prevent a sudden starting, and yet still requires a fine acceleration operation by an occupant. Moreover, in a case where this sort of vehicle parking is attempted on a slope, hill-climbing ability and/or anti-reverse-movement ability are required. Therefore, while an occupant is required to perform a challenging operation, a driving support by such a driving support apparatus is desired. Further, as described above, if the upper limit of an opening degree of a throttle valve, or a gain for a valve opening degree, is decreased, a torque to be generated is reduced. Therefore, there is a possibility that a vehicle cannot drive up the slope or steps. As described above, considering an application of this apparatus to a vehicle that drives up the slope, further developments are needed to the apparatuses disclosed in JP2000-136738A.
A need thus exists to provide a driving support apparatus, according to which a parking operation can be performed accurately, while a fine driving operation by an occupant can be reduced, regardless of a flatland or a slope on which the vehicle travels.